水合偏硼酸钾的热化学研究

Hydrated potassium monoborate(KBO₂·4/3H₂O) was obtained from an aqueous solution in a mole ratio of K₂O∶B₂O₃=2∶1 and characterized by powder X-ray diffraction(XRD)， infrared spectroscopy(FT-IR) and Raman spectroscopy. The enthalpy of solution of hydrated potassium monoborate， KBO₂·4/3H₂O， in approximately 1mol·dm^-3 aqueous hydrochloric acid was determined. Together with the previously determined enthalpies of so-lution of H₃BO₃ in approximately 1mol·dm^-3 HCl(aq) ，and of KCl in aqueous(hydrochloric acid+boric acid)， the standard molar enthalpy of formation of -(1411.11±0.84)kJ·mol^-1 for KBO₂·4/3H₂O was obtained from the standard molar enthalpies of formation of KCl(s)， H₃BO₃(s)， and H₂O(l). The standard molar entropy of formation of -422.94J·K^-1·mol^-1 and standard molar entropy of 163.47J·K^-1·mol^-1 for KBO₂·4/3H₂O were calculated from the thermodynamic relations. A group contribution method is applicable to KBO₂·4/3H₂O.

Study on Thermochemistry of Hydrated Potassium Monoborate

Hydrated potassium monoborate(KBO2 @ 4/3H2O) was obtained from an aqueous solution in a mole ratio ofK2O:B2O3 = 2:1 and characterized by powder X-ray diffraction(XRD), infrared spectroscopy(FT-IR) and Ramanspectroscopy. The enthalpy of solution of hydrated potassium monoborate, KBO2 @ 4/3H2O, in approximatelylmol @ dm-3 aqueous hydrochloric acid was determined. Together with the previously determined enthalpies of so-lution of H3BO3 in approximately 1mol @ dm-3 HCl(aq) , and of KCl in aqueous(hydrochloric acid + boric acid),the standard molar enthalpy of formation of - (1411.11 ± 0. 84)kJ @ mol-1 for KBO2 @ 4/3H2O was obtained fromthe standard molar enthalpies of formation of KCl(s), H3BO3(s), and H2O(1) The standard molar entropy offormation of -422. 94J @ K-1 @ mol-1 and standard molar entropy of 163.47J @ K-1 @ mol-1 for KBO2 @ 4/3H2Owere calculated from the thermodynamic relations. A group contribution method is applicable to KBO2 @ 4/3H2O.